Anonymous
Anonymous asked in Science & MathematicsPhysics · 5 months ago

# Why earth drags a helicopter along when the helicopter hovers in the air and it's stationary?

I know this is a common question and there are many answers online but I don't understand them because my physics isn't not good enough. Can you provide a simplified explanation for this for why a helicopter stays in the same position even if it's above the ground idly?

Relevance
• 5 months ago

It's the same reason the fly in your car is just buzzing around in the same place near your face even though the car is going 80 mph on the freeway. But let's start back at the beginning.

So you hop into your Lamborghini, fasten you seat belt, and reach over to start that 800 HP V10. As you do you notice a fly sitting on the steering wheel. No big deal; so you start your behemoth. And accelerate 0 to 80 in 2.5 seconds.

The fly is still there on the steering wheel. So you, the car, and the fly are doing 80 mph together. This is important, you and the fly are both doing 80 mph now.

Now the fly, bored a bit, springs straight up from the steering wheel and hovers there in front of your face. But you, the car, and the fly are still going 80 mph down the freeway. The fly sprang straight upward to hover, it did nothing fore and aft in the direction of the car to slow or speed it up...relative to the car.

And like that fly, that's why a helo just hovers above the ground it rose from.

Like the fly on the steering wheel is going 80 mph with the 80 mph car speed, the helo on the ground is going 1000 mph with the 1000 mph rotation of the planet.

This is important...because the planet is rotating at 1000 mph and the helo is just riding along on the ground, it's also going 1000 mph like that fly that was also going 80 mph with the car. And when the helo and the planet are both going the same speed in the same direction they are going zero mph relative to each other.

So now the helo pilot moves the collective and the helo lifts directly up, vertical from the ground. Because it goes vertical relative to the ground, that does not add or subtract speed from that 1000 mph it was going when on the ground. So it's still going 1000 mph.

Because the planet is rotating at 1000 mph and the helo is still hovering at 1000 mph in the same direction as the rotation, the relative velocity between the helo and the Earth remains at zero mph.

And that is in essence why the helo stays directly above its launch site when it hovers.

NOTE: It's a bit more complex then that, but that is the basic idea.

• D g
Lv 7
5 months ago

think of it like you are on a train .. the train gets moving ... then stays at steady speed.. you get up and walk down the train car and hardly know you re moving as fast as the train...

this is because the seat got you moving to the trains speed ..now luckily we were not accelerate like that or it would have been rough for the occupants of the earth .. when we were born and when things were made on the earth by us the earth is moving at a steady speed with only a slight direction change do to orbit which is sufficiently large so we dont feel the acceleration then

• 5 months ago

There are two reasons.

1. "Every body will continue to move in a straight line with constant speed UNLESS acted upon by a force".

The helicopter is moving with the earth when it is on the ground. It must continue moving with the earth unless we provide some force to alter its velocity.

2. Friction.

Even if we supply that force the air is moving with the earth. The air provides frictional force if you attempt to move RELATIVE TO THAT AIR.

So if you put a balloon up it does not stay still relative to the earth. It stays still relative to the AIR. (Big Big difference ).

To remain stationary relative to the earth the helicopter must use its engines to provide a force to counter the frictional forces of the air. And of course you cannot succeed with this in a gale force wind.

• 5 months ago

The air mass (atmosphere) is moving with the earth. It is pushed along by the trees, grasses and mountains at the same speed as the earth except where the winds caused by hi and lo pressure areas change it. the air is moving so it carries the Helicopter with it. It appears to be stationary above the earth.

• Dixon
Lv 7
5 months ago

Inertia .

• 5 months ago

When you shoot a shot gun, the various little balls of lead shot more or less stay together as a group as they travel to their target. Similarly, the Earth and the helicopter and the atmosphere are all moving together at the same speed, just like the little balls of shot are doing as they travel.

• Anonymous
5 months ago

The atmosphere is moving at the same speed as the Earth is rotating.

• 5 months ago

The helicopter, and the air around it, is already moving with the Earth. So they keep going, because there is no force to slow them down. That's what things do in the real world ... keep moving until a force slows them.

• 5 months ago

The atmosphere moves along with the planet.

• Mark
Lv 7
5 months ago

Because the helicopter, like everything else on the planet, is moving WITH the planet. Did you know that if the Earth suddenly stopped rotating, everyone would be red jelly on the walls that were still standing?

• oldprof
Lv 7
5 months agoReport

OR launched into deep space....